The invention relates to an airbag module comprising a flexible housing and a cover.
The airbag module is part of a vehicle occupant restraint system (coll. referred to as “airbag”) which is used to protect the vehicle occupant in particular vehicle situations. The vehicle occupant restraint system comprises, to simplify matters, a controller, an inflator and an airbag. The controller decides whether a situation is given in which the inflator is activated. The latter then inflates the airbag.
In the initial state the airbag is arranged in compactly folded form in a housing. The housing is arranged on or in the vicinity of a cover which may have different designs depending on the respective mounting situation and the type of airbag. When a driver airbag is concerned, the cover is a component which is arranged on the steering wheel hub. When a passenger airbag is concerned, the cover is part of the instrument panel. When a side airbag is concerned which is intended to be active in the case of side impact, the cover may be part of the vehicle seat or else part of the inner lining of the vehicle. When a knee airbag is concerned, the cover is a separate part which is arranged in a recess either in the lower portion of an instrument panel or in a lining part in the foot space of the vehicle.
While initially solid parts were used for the housing of the airbag, for example a sheet-metal trough, meanwhile also housings are known which are formed by an appropriately cut fabric part. Examples hereof are found in U.S. Pat. No. 7,530,500 B2.
A fabric housing offers the advantage that it is very light. Nevertheless, it is adapted to absorb the reaction forces occurring upon deployment of the airbag and to form the so called channel of ascent, i.e. to guide the airbag out of the housing during deployment.
With respect to a reliable function it is essential that the fabric part forming the airbag housing is tightly attached to the cover so that the forces occurring during deployment of the airbag which attempt to separate the housing from the cover can be reliably absorbed. At the same time it is desirable with respect to the mounting operation that the housing can be arranged on the cover with little effort.
It is known from the afore-mentioned U.S. Pat. No. 7,530,599 B2 to arrange the fabric housing on a frame which in turn can be arranged on the cover. This results in a comparatively complicated structure.